/*
 * Copyright 2002-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package sf.r2dbc.binding;

import io.r2dbc.spi.Statement;
import org.springframework.util.Assert;

import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.function.Function;

/**
 * Name-based bind markers.
 * @author Mark Paluch
 * @since 5.3
 */
class NamedBindMarkers implements BindMarkers {

    private static final AtomicIntegerFieldUpdater<NamedBindMarkers> COUNTER_INCREMENTER =
            AtomicIntegerFieldUpdater.newUpdater(NamedBindMarkers.class, "counter");


    private final String prefix;

    private final String namePrefix;

    private final int nameLimit;

    private final Function<String, String> hintFilterFunction;

    // access via COUNTER_INCREMENTER
    @SuppressWarnings("unused")
    private volatile int counter;


    NamedBindMarkers(String prefix, String namePrefix, int nameLimit, Function<String, String> hintFilterFunction) {
        this.prefix = prefix;
        this.namePrefix = namePrefix;
        this.nameLimit = nameLimit;
        this.hintFilterFunction = hintFilterFunction;
    }


    @Override
    public BindMarker next() {
        String name = nextName();
        return new NamedBindMarker(this.prefix + name, name);
    }

    @Override
    public BindMarker next(String hint) {
        Assert.notNull(hint, "Name hint must not be null");
        String name = nextName() + this.hintFilterFunction.apply(hint);

        if (name.length() > this.nameLimit) {
            name = name.substring(0, this.nameLimit);
        }

        return new NamedBindMarker(this.prefix + name, name);
    }

    private String nextName() {
        int index = COUNTER_INCREMENTER.getAndIncrement(this);
        return this.namePrefix + index;
    }


    /**
     * A single named bind marker.
     */
    static class NamedBindMarker implements BindMarker {

        private final String placeholder;

        private final String identifier;

        NamedBindMarker(String placeholder, String identifier) {
            this.placeholder = placeholder;
            this.identifier = identifier;
        }

        @Override
        public String getPlaceholder() {
            return this.placeholder;
        }

        @Override
        public void bind(Statement target, Object value) {
            target.bind(this.identifier, value);
        }

        @Override
        public void bindNull(Statement target, Class<?> valueType) {
            target.bindNull(this.identifier, valueType);
        }
    }

}
